The eigenvalues of particle size distribution were analyzed for the sediment of Yellow River from 1950 to 2005 and the formula addressing mean annual sediment input in any reach of the Yellow River were developed to account the sediment sources inputting into the Ningxia-Inner Mongolia reach of the Yellow River. The results show that a huge amount of sediment was delivered into the Ningxia-Inner Mongolia reach annually from 1950 to 2005

and the mean annual sediment input amount varied with time. With data mining and field investigation

we found that the variations were results from the interaction between desert and river as Yellow River flows through the deserts such as Tengger Desert

Hedong sandyland

Ulan Buh Desert and Kubuqi Desert in Ningxia and Inner Mongolia Autonomous Region

where aeolian sediment trans-portation was a major input source into the river. Furthermore

in the upper reach of ＂Ten Great Gullies＂ with great bed gradients

the aeolian sediment covering river banks can be eroded easily by both wind and water and carried into Yellow River by floods. In summary

we think that the key to control channel aggra-dation of Yellow River is reducing the amount sediment input into the Ningxia-Inner Mongolia reach

which in turn can be achieved through comprehensive prevention measures such as soil and water conservation

eco-system restoration and engineering measures

which especially should be strengthened in the ＂Ten Great Gullies＂ region.